This invention relates to an implantable system for use in the performance of in vivo measurements beneath the skin. More particularly, there is included a system for performing measurements of blood flow velocity.
There are a number of reasons for implanting instrumentation in the body. It may be that the instrumentation is to be active over an extended period, either continuously or repeated from time to time. It may be considerably more desirable to activate the instrumentation, such as a measurement system, during more or less normal activity, rather than being restricted to using the instrumentation in the body in a surgical environment.
There are also a number of problems associated with implaning instrumentation. Many of these have to do with the inviolability of the skin. It is most desirable that the skin completely heal over an implantation insertion and that no wires or other devices pass through the skin, requiring openings in its protective barrier of the body. As a result, there are abiding problems of supplying power from the outside into the implanted instrumentation and of transmitting information through the skin, usually from beneath the skin to the outside.